An antenna tuner impedance matching network

Abstract

The application relates to an antenna tuner impedance matching network, belonging to the technical field of communication equipment, which comprises a series adjustable inductor, a parallel adjustable capacitor, a series adjustable capacitor and a network topology switching unit, the first end of the series adjustable inductor is connected with a radio frequency input end and the first end of the network topology switching unit, the second end is connected with the first end of the series adjustable capacitor and the second end of the network topology switching unit; the second end of the series adjustable capacitor is connected with a radio frequency output end; the third end of the network topology switching unit is connected with the parallel adjustable capacitor, and the network topology switching unit is used for switching between at least two connection states, so as to selectively connect the parallel adjustable capacitor to between the first end of the series adjustable inductor and the radio frequency input end or between the second end of the series adjustable inductor and the series adjustable capacitor. The application can flexibly switch different impedance matching networks, realizes more accurate impedance matching adjustment, and improves the communication quality of the antenna tuner.

Description

Technical Field

[0001] This application relates to the technical field of communication equipment, and in particular to an antenna tuner impedance matching network. Background Technology

[0002] In mobile communications, the Internet of Things, and other wireless communication systems, the antenna tuner is a key component of the radio frequency front end. Its main function is to adjust the input impedance of the antenna to match the output impedance of the radio frequency transceiver link, which is typically 50 ohms, in order to achieve maximum power transmission and reduce signal reflection.

[0003] Some antenna tuners employ fixed-topology matching networks, such as fixed Γ-type or inverse Γ-type networks, achieving impedance matching by adjusting variable capacitors or inductors within the network. These two types of networks each have their own preferred transformation regions for impedance matching: Γ-type networks are typically used to transform low impedance to high impedance, while inverse Γ-type networks are used to transform high impedance to low impedance. Therefore, the impedance region that a tuner using a single fixed topology can efficiently match on the Smith chart is limited. When the antenna load experiences significant impedance drift due to frequency changes or external environmental influences such as human hands or metal, a single topology network may not be able to provide effective matching, leading to a degraded communication quality. Utility Model Content

[0004] To improve the impedance matching effect of the antenna tuner and thus enhance the communication quality of the antenna tuner, this application provides an antenna tuner impedance matching network.

[0005] An antenna tuner impedance matching network includes a series adjustable inductor, a parallel adjustable capacitor, a series adjustable capacitor, and a network topology switching unit. The first end of the series adjustable inductor is connected to the RF input terminal of the antenna tuner and the first end of the network topology switching unit, respectively. The second end of the series adjustable inductor is connected to the first end of the series adjustable capacitor and the second end of the network topology switching unit, respectively. The second end of the series adjustable capacitor is connected to the RF output terminal of the antenna tuner. The third end of the network topology switching unit is connected to the first end of the parallel adjustable capacitor, and the second end of the parallel adjustable capacitor is grounded. The series adjustable inductor, the parallel adjustable capacitor, and the series adjustable capacitor are each connected to a control switch to short-circuit or connect the corresponding capacitor or inductor to the circuit. The network topology switching unit is used to enable the antenna tuner to provide impedance matching adjustment function corresponding to the first impedance matching network in the first connection state, and to enable the antenna tuner to provide impedance matching adjustment function corresponding to the second impedance matching network in the second connection state.

[0006] By adopting the above technical solution, an impedance matching network for the antenna tuner is constructed using a series adjustable inductor, a parallel adjustable capacitor, a series adjustable capacitor, and a network topology switching unit. The control switch can short-circuit or connect the corresponding capacitor or inductor to the circuit. The network topology switching unit can enable the antenna tuner to provide different impedance matching network adjustment functions under different states, thereby flexibly connecting the parallel adjustable capacitor to different positions in the circuit. It is no longer limited to the limited matching area of ​​a single fixed topology network, but achieves effective coverage of a wider range of impedance points, improving the signal transmission efficiency and communication quality of the antenna when working in complex and variable environments.

[0007] Optionally, both the network topology switching unit and the control switch are relays.

[0008] By adopting the above technical solution and using relays as network topology switching units and control switches, the advantages of relays—low on-resistance, high off-isolation, and high power capacity—are utilized, thereby effectively reducing signal insertion loss, preventing signal crosstalk, and improving the reliability and electrical performance of the entire matching network.

[0009] Optionally, in the first connection state, when the first end and the third end of the network topology switching unit are connected, the antenna tuner impedance matching network is the first impedance matching network; in the second connection state, when the second end and the third end of the network topology switching unit are connected, the antenna tuner impedance matching network is the second impedance matching network.

[0010] By adopting the above technical solution, different ends of the network topology switching unit are connected, so that the antenna tuner impedance matching network is the first impedance matching network and the second impedance matching network in the first connection state and the second connection state, respectively. It is possible to switch the type of access impedance matching network as needed, thereby achieving full coverage of the impedance matching area.

[0011] Optionally, in the first connection state, the first end of the series adjustable inductor is connected to the RF input terminal and the first end of the parallel adjustable capacitor, the second end of the parallel adjustable capacitor is grounded, the second end of the series adjustable inductor is connected to the first end of the series adjustable capacitor, and the second end of the series adjustable capacitor is connected to the RF output terminal.

[0012] By adopting the above technical solution, when the network topology switching unit is in the first connection state, the antenna tuner can provide the impedance matching adjustment function corresponding to the first impedance matching network, realize the specific circuit connection structure in the first connection state, and together with the setting of series adjustable inductor, parallel adjustable capacitor and series adjustable capacitor, provide support for the impedance matching of the antenna tuner.

[0013] Optionally, in the second connection state, the first end of the series adjustable inductor is connected to the RF input terminal, the second end of the series adjustable inductor is connected to the first end of the series adjustable capacitor and the first end of the parallel adjustable capacitor, the second end of the parallel adjustable capacitor is grounded, and the second end of the series adjustable capacitor is connected to the RF output terminal.

[0014] By adopting the above technical solution, when the network topology switching unit is in the second connection state, the antenna tuner can provide the impedance matching adjustment function corresponding to the second impedance matching network, realize the specific circuit connection structure in the second connection state, and together with the setting of series adjustable inductor, parallel adjustable capacitor and series adjustable capacitor, provide support for the impedance matching of the antenna tuner.

[0015] Optionally, the series adjustable inductor consists of multiple inductors connected in series, and the inductance value of the inductor is determined using a binary step relationship.

[0016] By adopting the above technical solution, a series adjustable inductor is constructed by using multiple inductors connected in series with their inductance values ​​determined by a binary step relationship. This enables wide-range, high-resolution inductance value adjustment with the fewest number of components, greatly simplifying circuit design and reducing production costs and physical size. Combined with a network topology switching unit, parallel adjustable capacitors, and series adjustable capacitors, the impedance matching adjustment function of the antenna tuner under different states can be realized, thereby achieving coverage of the impedance matching region.

[0017] Optionally, the parallel adjustable capacitor consists of multiple capacitors connected in parallel in sequence, and the capacitance value of the capacitor is determined by a binary step relationship.

[0018] By adopting the above technical solution, using multiple capacitors connected in parallel with their capacitance values ​​determined by a binary step relationship to form a parallel adjustable capacitor, a wide range and high resolution inductance value adjustment can be achieved with the fewest components. This greatly simplifies circuit design, reduces production costs and physical size. Combined with a network topology switching unit, a series adjustable inductor and a series adjustable capacitor, the impedance matching adjustment function of the antenna tuner in different states can be realized, thereby achieving coverage of the impedance matching region.

[0019] Optionally, the series adjustable capacitor is composed of multiple capacitors connected in parallel in sequence, and the capacitance value of the capacitor is determined by a binary step relationship.

[0020] By adopting the above technical solution, using multiple capacitors connected in parallel with their capacitance values ​​determined by a binary step relationship to form a parallel adjustable capacitor, a wide range and high resolution inductance value adjustment can be achieved with the fewest components. This greatly simplifies circuit design, reduces production costs and physical size. Combined with a network topology switching unit, a series adjustable inductor and a parallel adjustable capacitor, the impedance matching adjustment function of the antenna tuner in different states can be realized, thereby achieving coverage of the impedance matching region.

[0021] In summary, this application includes at least the following beneficial effects: 1. An impedance matching network for an antenna tuner is constructed using a series adjustable inductor, a parallel adjustable capacitor, a series adjustable capacitor, and a network topology switching unit. A control switch can short-circuit or connect the corresponding capacitor or inductor to the circuit. The network topology switching unit enables the antenna tuner to provide different impedance matching network adjustment functions under different states. This allows for flexible selective connection of the parallel adjustable capacitor to different positions in the circuit, no longer limited to the limited matching area of ​​a single fixed topology network. This achieves effective coverage of a wider range of impedance points, improving the signal transmission efficiency and communication quality of the antenna in complex and variable environments. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the Γ-type matching network in the embodiments of this application; Figure 2 This is a schematic diagram of the structure of the inverse Γ-type matching network in the embodiments of this application; Figure 3 This is a schematic diagram of the impedance matching region in the embodiments of this application; Figure 4 This is a block diagram of the impedance matching network of the antenna tuner in an embodiment of this application; Figure 5 This is a schematic diagram of the circuit structure of the impedance matching network of the antenna tuner in the embodiments of this application. Detailed Implementation

[0023] This application is combined with Figures 1-5 Let's take an example to explain in more detail.

[0024] The basic structure of a Γ-type matching network is as follows: Figure 1 As shown, the basic structure of the inverse Γ-type matching network is as follows: Figure 2 As shown. In an exemplary Smith chart, as... Figure 3As shown, the effective matching region of the Γ-type network is indicated by the blank area, while the effective matching region of the inverse Γ-type network is indicated by the horizontal line area. Therefore, a single Γ-type matching network cannot completely cover the entire impedance matching region. Therefore, this application provides an antenna tuner impedance matching network that employs two basic and efficient matching topologies: a Γ-type matching network with a series capacitor and an inverse Γ-type matching network. The structure of the connected matching network can be changed through relay control, achieving full-load-point impedance matching in the complex plane and improving signal transmission efficiency.

[0025] Reference Figure 4 The antenna tuner impedance matching network includes a series adjustable inductor 1, a parallel adjustable capacitor 2, a series adjustable capacitor 3, and a network topology switching unit 4. The first end of the series adjustable inductor 1 is connected to the RF input terminal and also to the first end of the network topology switching unit 4. The second end of the series adjustable inductor 1 is connected to the first end of the series adjustable capacitor 3 and also to the second end of the network topology switching unit 4. The second end of the series adjustable capacitor 3 is connected to the RF output terminal of the antenna tuner. The third end of the network topology switching unit 4 is connected to the first end of the parallel adjustable capacitor 2, while the second end of the parallel adjustable capacitor 2 is grounded. Through this connection method, the various components cooperate with each other, and the network topology switching unit 4 can change the network topology to adapt to different impedance matching conditions.

[0026] Reference Figure 5As one implementation of the network topology switching unit 4, the network topology switching unit 4 can be a relay, used to enable the antenna tuner to provide the impedance matching adjustment function corresponding to the first impedance matching network in the first connection state, and to enable the antenna tuner to provide the impedance matching adjustment function corresponding to the second impedance matching network in the second connection state. When the network topology switching unit 4 is in the first connection state, its first and third terminals are connected. At this time, the antenna tuner impedance matching network is the first impedance matching network, that is, the first terminal of the series adjustable inductor 1 is connected to the RF input terminal, and is also connected to the first terminal of the parallel adjustable capacitor 2 through the network topology switching unit 4. The second terminal of the parallel adjustable capacitor 2 is grounded, the second terminal of the series adjustable inductor 1 is connected to the first terminal of the series adjustable capacitor 3, and the second terminal of the series adjustable capacitor 3 is connected to the RF output terminal. When the network topology switching unit 4 is in the second connection state, its second and third terminals are connected. At this time, the antenna tuner impedance matching network is the second impedance matching network, that is, the first terminal of the series adjustable inductor 1 is connected to the RF input terminal, the second terminal of the series adjustable inductor 1 is connected to the first terminal of the series adjustable capacitor 3, and is also connected to the first terminal of the parallel adjustable capacitor 2 through the network topology switching unit 4. The second terminal of the parallel adjustable capacitor 2 is grounded, and the second terminal of the series adjustable capacitor 3 is connected to the RF output terminal. By switching between the two states using the network topology switching unit 4, the antenna tuner can provide different impedance matching adjustment functions to adapt to different impedance matching requirements.

[0027] In this embodiment, in the first connection state, the entire impedance matching network forms a specific topology, wherein the parallel adjustable capacitor 2 is located before the series adjustable inductor 1 and the series adjustable capacitor 3, forming a Γ-type matching network, that is, forming a cascaded structure of the parallel adjustable capacitor 2, the series adjustable inductor 1, and the series adjustable capacitor 3. This structure is particularly suitable for matching the lower antenna impedance to the characteristic impedance of the RF transceiver link, for example, matching the impedance region inside the 50-ohm characteristic impedance point on the Smith chart, thereby effectively dealing with the low impedance characteristics exhibited by the antenna in certain frequency bands or environments; in the second connection state... In the connected state, the topology of the entire impedance matching network changes significantly. The parallel adjustable capacitor 2 is placed between the series adjustable inductor 1 and the series adjustable capacitor 3, forming an inverse Γ-type matching network. That is, a cascaded structure of series adjustable inductor 1, parallel adjustable capacitor 2, and series adjustable capacitor 3 is formed. This inverse Γ-type topology complements the Γ-type network in the first state and is particularly good at matching high antenna impedance to the characteristic impedance. For example, it matches the impedance region outside the 50-ohm characteristic impedance point on the Smith chart, thereby effectively dealing with the high impedance characteristics that the antenna may exhibit in other frequency bands or environments.

[0028] In order to achieve precise control of the reactive components in the network, the series adjustable inductor 1, the parallel adjustable capacitor 2 and the series adjustable capacitor 3 are respectively connected to control switches. By closing or opening these switches, the corresponding capacitor or inductor can be short-circuited or connected to the circuit, thereby changing the total inductance or capacitance value.

[0029] Reference Figure 5 As one embodiment of the series-adjustable inductor 1, the series-adjustable inductor 1 consists of multiple inductors connected in series sequentially, and the inductance values ​​of the inductors are determined using a binary step relationship. The inductors can be air-core inductors or magnetic core inductors. Air-core inductors have a simple structure and small distributed capacitance, making them suitable for high-frequency circuits; magnetic core inductors can achieve larger inductance values ​​in a smaller volume, making them suitable for applications with high space requirements. The inductance values ​​of these inductors are determined using a binary step relationship; for example, there can be a minimum inductance value L. min The subsequent inductance values ​​are 2L. min 4L min wait.

[0030] In this embodiment, each inductor is connected to a corresponding control switch, which can be a relay. When the relay is energized, the corresponding inductor is connected to the circuit; when the relay is de-energized, the corresponding inductor is short-circuited. By controlling the on / off state of different relays, the inductance value connected to the circuit can be flexibly adjusted. By controlling the on / off state of the corresponding relays, it is possible to obtain a total of 2 inductors, from all inductors being short-circuited to all inductors being connected to the circuit. n With a different inductance value, where n is the number of inductors, this binary step design can achieve the largest tuning range and the finest tuning steps with the fewest number of components, greatly optimizing the complexity and cost of the circuit.

[0031] Reference Figure 5 As one implementation of the parallel adjustable capacitor 2, the parallel adjustable capacitor 2 consists of multiple capacitors connected in parallel sequentially, and the capacitance values ​​of the capacitors are determined using a binary step relationship. The capacitors can be ceramic capacitors or mica capacitors. Ceramic capacitors are characterized by their small size and large capacitance; mica capacitors have good stability and low loss. The capacitance values ​​of these capacitors are determined using a binary step relationship, and the minimum capacitance value is set to C. min The subsequent capacitance values ​​are 2C. min 4C min wait.

[0032] In this embodiment, each capacitor is also connected to a corresponding control switch, which can also be a relay. The on / off state of the relay determines whether a capacitor is connected to the circuit, thereby adjusting the capacitance value of the parallel adjustable capacitor 2. Similarly, by controlling the on / off state of the corresponding relay, the circuit can be adjusted from all capacitors disconnected to all capacitors connected, for a total of 2 capacitors. nWith n different capacitance values, where n is the number of capacitors, this binary configuration method also ensures high-resolution capacitance adjustment capability while occupying minimal circuit area and cost, allowing impedance matching algorithms to find the optimal matching point more accurately.

[0033] Reference Figure 5 As one implementation of the series adjustable capacitor 3, the series adjustable capacitor 3 consists of multiple capacitors connected in parallel sequentially, and the capacitance value of the capacitors is determined using a binary step relationship. The capacitors here can also be ceramic capacitors or mica capacitors. Their capacitance values ​​are also determined using a binary step relationship, starting with the minimum capacitance value and increasing according to a binary rule. Each capacitor is also controlled by a corresponding control switch, which can be a relay. By controlling the on / off state of the relay, the capacitance value of the series adjustable capacitor 3 connected to the circuit is changed.

[0034] The implementation principle of this embodiment is as follows: By employing series adjustable inductors, parallel adjustable capacitors, and series adjustable capacitors, and utilizing binary step relationships to determine component values, combined with the switching function of the network topology switching unit, the network structure and component access can be flexibly adjusted according to different impedance matching points. When the impedance matching points are in different regions, the network topology switching unit switches to the corresponding state. Simultaneously, by controlling the on / off state of the relays corresponding to each component, the inductor and capacitor values ​​are precisely adjusted, thereby achieving impedance matching for all load points in the complex plane. This significantly improves the efficiency and quality of signal transmission, representing a significant improvement compared to traditional single-structure matching networks.

[0035] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An impedance matching network for an antenna tuner, characterized in that, It includes a series adjustable inductor, a parallel adjustable capacitor, a series adjustable capacitor, and a network topology switching unit; The first end of the series adjustable inductor is connected to the RF input terminal of the antenna tuner and the first end of the network topology switching unit, respectively. The second end of the series adjustable inductor is connected to the first end of the series adjustable capacitor and the second end of the network topology switching unit, respectively. The second end of the series adjustable capacitor is connected to the RF output terminal of the antenna tuner. The third end of the network topology switching unit is connected to the first end of the parallel adjustable capacitor, and the second end of the parallel adjustable capacitor is grounded. The series adjustable inductor, the parallel adjustable capacitor, and the series adjustable capacitor are each connected to a control switch to short-circuit or connect the corresponding capacitor or inductor to the circuit. The network topology switching unit is used to enable the antenna tuner to provide impedance matching adjustment function corresponding to the first impedance matching network in the first connection state, and to enable the antenna tuner to provide impedance matching adjustment function corresponding to the second impedance matching network in the second connection state.

2. The antenna tuner impedance matching network according to claim 1, characterized in that, Both the network topology switching unit and the control switch are relays.

3. The antenna tuner impedance matching network according to claim 1, characterized in that, In the first connection state, when the first end and the third end of the network topology switching unit are connected, the antenna tuner impedance matching network is the first impedance matching network. In the second connection state, when the second end and the third end of the network topology switching unit are connected, the antenna tuner impedance matching network is the second impedance matching network.

4. The antenna tuner impedance matching network according to claim 3, characterized in that, In the first connection state, the first end of the series adjustable inductor is connected to the RF input terminal and the first end of the parallel adjustable capacitor, the second end of the parallel adjustable capacitor is grounded, the second end of the series adjustable inductor is connected to the first end of the series adjustable capacitor, and the second end of the series adjustable capacitor is connected to the RF output terminal.

5. The antenna tuner impedance matching network according to claim 3, characterized in that, In the second connection state, the first end of the series adjustable inductor is connected to the RF input terminal, the second end of the series adjustable inductor is connected to the first end of the series adjustable capacitor and the first end of the parallel adjustable capacitor, the second end of the parallel adjustable capacitor is grounded, and the second end of the series adjustable capacitor is connected to the RF output terminal.

6. The antenna tuner impedance matching network according to claim 1, characterized in that: The series adjustable inductor is composed of multiple inductors connected in series, and the inductance value of the inductor is determined by a binary step relationship.

7. The antenna tuner impedance matching network according to claim 1, characterized in that: The parallel adjustable capacitor consists of multiple capacitors connected in parallel in sequence, and the capacitance value of the capacitor is determined by a binary step relationship.

8. The antenna tuner impedance matching network according to claim 1, characterized in that: The series adjustable capacitor is composed of multiple capacitors connected in parallel in sequence, and the capacitance value of the capacitor is determined by a binary step relationship.

Images